This paper reports the first karyological study of trematode Ichthyocotylurus platycephalus (Creplin, 1825) Odening 1969. Chromosome number and morphology were studied in somatic cells of parthenites from intermediate host--mollusc Valvata piscinalis using an air drying technique and Giemsa staining. The karyotype consisted of 20 chromosomes comprising five pairs of subtelo-acrocentric (1st to ...

Triploid Atlantic salmon (Salmo salar L.) may play an important role in the sustainable expansion of the Norwegian aquaculture industry. Therefore, the susceptibility of triploid salmon to common infections such as salmonid alphavirus (SAV), the causative agent of pancreas disease (PD), requires investigation. In this study, shortly after seawater transfer, diploid and triploid post-smolts were...

The yeast S. cerevisiae is a central model organism in eukaryotic cell studies and a major component in many food and biotechnological industrial processes. However, the wide knowledge regarding genetics and molecular biology of S. cerevisiae is based on an extremely narrow range of strains. Studies of natural populations of S. cerevisiae, not associated with human activities or industrial ferm...

Study was done to show the effect of triploidy on growth performance, survival rate and gender ratio on Penaeus merguiensis compared to diploid sibling otherwise identifying the sex external characteristic of the postlarval. Cold shocks (10°C, 15°C and 20°C) with control (28°C) and three different time of exposures (10, 15 and 20 min)were introduced to each treatments. The fertilization rate wa...

The present study investigated nutritional programming in Atlantic salmon to improve utilisation of a vegetable-based diet. At first exogenous feeding, fry were fed either a marine-based diet (Diet Mstimulus, 80% fishmeal (FM)/4% fish oil (FO)) or a vegetable-based diet (Diet Vstimulus, 10% FM/0% FO) for 3 weeks. Subsequently, all fish were then fed under the same conditions with a commercial, ...

During normal development of the supraorbital lateral line system of Xenopus, an elongated streak of primordial cells becomes subdivided into a linear series of cell groups containing only about eight cells each, thus forming a row of primary lateral line organs (Winklbauer & Hausen, 1983a,b). In triploid Xenopus embryos, cell size is 1.5 X normal. When the formation of lateral line organs occu...

Chromosome cytology was examined in two species of the Aster ageratoides complex, A. ageratoides Turcz. (= A. leiophyllus Franch. et Sav.) and A. lasioclada Hayata, in Taiwan. Of the 70 individuals of A. ageratoides sampled, one was found to be diploid (2n = 18) and the rest tetraploid (2n = 36, 37). The occurrence of the diploid A. ageratoides in Taiwan appears to be ancient. Eighteen individu...

This paper presents a study of the influence of chromosome balance on duration of life in Drosophila. The balanced type of cells are shown to favor a longer life than are the unbalanced type. Under the identical conditions of the experiment, the type females live an average of 33.1+/-.6 days; the type males 28.9+/-.8 days; the triploid females 33.1+/-.8 days and the sex-intergrade females 15.0+...

Characteristics of parthenogenesis in Cacopsylla ledi (Flor, 1861) were analyzed using cytological and molecular approaches. In all three populations studied from Finland, i.e. Turku, Kustavi and Siikajoki, males were present at a low frequency but were absent from a population from Vorkuta, Russia. In a follow-up study conducted in the Turku population during 2010-2016, the initial frequency o...

The role of the planarian neoblast as a totipotential stem cell has been discussed in the literature for well over a century (cf. Brondsted's excellent review, 1955). It remained a matter of strong debate until 1949 when Dubois demonstrated conclusively the migration of neoblasts (through regions depleted of their neoblasts by radiation) to the surface of a wound. She showed that the onset of r...